OK, makes sense.

Thanks
/Ake

Spehro Pefhany wrote:

> At 11:10 PM 5/15/2005 +0200, you wrote:
>
>> Spehro,
>>
>> First of all thanks for noticing  the +/. swap. Had it on paper and=20
>> the component in eagle was the other way.  Probably should have taken=20
>> me several hours to find on a board... ;-(
>>
>> When you say adding a 2nd pole filter do you mean to replace the PWM=20
>> LPF?  My thought was to also remove ripple in software. In this case=20
>> it has known properties so this should be possible.
>
>
> If it's large you can run into nonlinearities when you don't expect to.
>
>> Where does the 11.8 come from in 100/11.8?
>
>
> In the DC path, the 1.8K is in series with the 10K (think of the=20
> capacitor
> as being open circuit for DC). If you put a buffer in there,
> as I suggested, it will reduce that to zero and eliminate the effect=20
> of the
> PIC port output impedance.
>
> That's the gain looking from a fictional DC PWM source. The gain from t=
he
> sensor will be half of (that number plus 1) because of the  voltage=20
> divider
> on the non-inverting input.
>
>
> Best regards,
>
> Spehro Pefhany --"it's the network..."            "The Journey is the=20
> reward"
> speff@interlog.com             Info for manufacturers:=20
> http://www.trexon.com
> Embedded software/hardware/analog  Info for designers: =20
> http://www.speff.com
> >>>Inexpensive test equipment & parts=20
> http://search.ebay.com/_W0QQsassZspeff
>
>


--=20
 ---
Ake Hedman (YAP - Yet Another Programmer)
eurosource, Brattbergav=E4gen 17, 820 50 LOS, Sweden
Phone: (46) 657 413430 Cellular: (46) 73 84 84 102
Company home: http://www.eurosource.se     =20
Kryddor/Te/Kaffe: http://www.brattberg.com
Personal homepage: http://www.eurosource.se/akhe
Automated home: http://www.vscp.org


--=20
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